Combining aptamer-modified gold nanoparticles with barcode DNA sequence amplification for indirect analysis of ethanolamine

Abstract

An indirect analysis strategy for small organic molecules is presented herein, combining aptamermodified gold nanoparticles (AuNPs) with a designed barcode sequence for amplification. Ethanolamine, which could not be analyzed directly through liquid chromatography coupled with mass spectrometry (LC/MS), was used as a model compound to demonstrate the feasibility of the proposed scheme. A poly adenosine barcode sequence was part of the designed cDNA Al (cDNA + barcode sequence) to provide a large number of adenine bases for signal amplification. In the presence of fixed amounts of the aptamer and cDNA Al, the concentration of ethanolamine could be estimated indirectly through measurement of the concentration of the hydrolyzed bases of the unbound cDNA Al. The thiol-terminated aptamer was immobilized on the AuNPs through Au-S self-assembly. The aptamer-immobilized AuNPs were removed, with their bound ethanolamine and cDNA Al, through centrifugation. The unbound cDNA Al remaining in the supernatant was hydrolyzed and analyzed. Through indirect analysis and amplification of the cDNA Al, the concentration of ethanolamine could be analyzed with a linear range (on a logarithmic scale) between 5 and 5000 nM (detection limit: 1.2 nM). This developed method might be applied as a general platform for indirect detection using LC/MS analysis. (C) 2017 Elsevier B.V. All rights reserved.